The US Department of Justice (DoJ) has asked Boeing to provide records of the assembling process of the 787 Dreamliner in South Carolina over "shoddy work", the Seattle Times reported Friday, citing source close to the investigation.
According to a source, the department already issued a number of subpoenas to individual workers of the South Carolina plant earlier in June.
The move comes as the authority is investigating the certification and design of another Boeing aircraft - the 737 MAX - after two deadly crashes earlier this year.
Thought it's currently unclear whether the two cases are being investigated by the same prosecutors, one of the sources noted that the subpoenas were issued by "the same team" of investigators involved in the 737 MAX probe.
Boeing has been struggling to get their global fleet of 737-MAX jets back in the air after months of grounding in the wake of two fatal incidents - an Ethiopian Airlines crash in March that closely followed the crash of a Lion Air flight in Indonesia in October.
Both crashes left no survivors, racking up a death toll of 346 people.